Power transmissions are often employed with drive systems to transfer power between an actuator or motor and an output shaft. For example, the rotary actuators transfer power from a rotary actuator or moving element to an output shaft. In some examples, rotary wing aircraft (e.g., helicopters) employ a rotor or output driven by an engine or input via a drive system. A drive system typically employs a transmission (e.g., a gearbox) that transfers power between an engine and the rotor. In some instances, the transmission also provides speed and/or torque varying functionality (e.g., increasing or decreasing between input and output). A transmission of rotary wing aircraft often has a relatively large dimensional envelope or footprint and/or weight. In some instances, the transmission is often the heaviest subsystem in a drive system of an aircraft.